1. Field of the Invention
The present invention relates to metal housings, particularly, to a metal housing made of a plurality of metal materials.
2. Description of Related Art
Portable electronic devices, such as mobile telephones, personal digital assistants, or MP3 players, enable consumers to enjoy the convenience of high technology services, almost anytime and anywhere. These electronic devices often employ a decorative housing to attract consumers. The housing may be made of a plastic or other polymeric material, of a metal such as stainless steel, aluminum, aluminum alloy, magnesium alloy or titanium alloy. Plastic or other polymeric materials are light and inexpensive, but have poor mechanical strength. In addition, housings made of plastic or other polymeric materials need surface treatments, such as plating, painting or the like to provide the housing with a decorative appearance. These surface treatments are complex. Due to their characteristics of heat resistance, wear resistance, high luster, EMI shielding performance and other decorative qualities, metal materials are widely used to manufacture housings of these electronic devices. However, a metal housing is typically formed by stamping a single metal plate made of a single metal material. Thus, the metal housing is provided with a single metallic appearance.
Therefore, a new metal housing for portable electronic device is desired in order to overcome the above-described problems.